Using mobile agent for locationspecific data retrieval in MANET

Location-specific data retrieval is an attractive application in a Mobile Ad-hoc Network (MANET). Simple solution for it is that an observer retrieves the data by geocasting from an observer node, but its overhead highly depends on location of the observer and the designated region. We propose a mobile agent approach. A mobile agent migrates from the observer node to a node in the designated region, retrieves data from there, and summarizes, filters, and compresses the retrieved data, This data is sent back to the observer, when the observer request. Since the data is retrieved by the mobile agent located near the data sources, the data retrieval in the mobile agent approach would involve low overhead, even if the observer is far from the target region or moves around. In the MANET, however, even after the first migration, to stay near data sources, a mobile agent should migrate to another node in response to node movements. In this paper, we propose the Geographically Bound Mobile Agent (GBMA) which is a mobile agent that migrates to always be located in a designated region. Moreover, to clarify where the GBMA should be located and when the GBMA starts to migrate, we introduce two geographic zones: required zone and expected zone. Compared with the conventional methods with geocast or with a conventional mobile agent, the GBMA with these zones for retrieving locationspecific data can reduce the total number of messages.